Cocking mechanisms for guns

ABSTRACT

A cocking mechanism for a gun, comprising a rotary shaft, carried by the mounting and having intersecting right and lefthanded screw-threads and a coacting retractor member which, on rotation of the shaft, retracts the recoiling parts of the weapon, as a result of its interaction with one screw-thread, to cock certain mechanisms; whereafter run-out occurs under the influence of spring action accompanied by interaction between the retractor member and the reverse thread. The first screw-thread may be of slow pitch to give a mechanical advantage to the operator and the reverse thread of steeper pitch to give a mechanical advantage in favor of the springs.

United States Patent Brint Oct. 24, 1972 [54] COCKING MECHANISMS FORGUNS Primary Examiner-Stephen C. Bentley [72] inventor: Norman TrevorBrint, Essex, En- 4n0mey4ushman D arby & Cushman gland [73] Assignee:The Secretary of State for Defense in [57] ABSTRACT Her BritannicMaiestys Govern- A cockin g mechanism for a gun, comprising a rotary BUn'ted Kmgdom of shaft, carried by the mounting and having intersectingGreat Bmam and Northern Ireland right and left-handed screw-threads anda coacting London England retractor member which, on rotation of theshaft, [22] Filed: Nov. 28, 1967 retracts the recoiling parts of theweapon, as a result of its interaction with one screw-thread, to cockcer- PP N04 686,356 tain mechanisms; whereafter run-out occurs under theinfluence of spring action accompanied by interaction between theretractor member and the reverse thread. [52] (5|. The first Screwthready be of slow pitch to g a [5 "20 42/16 3 mechanical advantage to theoperator and the reverse [58] new of Search 1 thread of steeper pitch togive a mechanical advantage [56] R f Cited in favor of the springs.

e erences UNITED STATES PATE 6 Claims, 2 Drawing Figures 4/ i890Victorin ..89/20 n will PATENTED um 24 I912 3 7 00 I3 94 SHEET 1 OF 2Inventor COCKING MECHANISMS FOR GUNS The invention relates to cockingmechanisms for guns.

In certain types of weapon, various mechanisms such as the breechmechanism, loading, extracting and ramming mechanisms require to..becocked preparatory to loading or reloading the weapon, an action which,during a firing sequence, may be performed by the recoil movement of thegun after firing the previous round. At the start of a firing sequence,however, it may be necessary to cock these mechanisms by other means andthe object of the present invention is to provide a cocking mechanismfor retracting the gun relative to a cradle or mounting against springaction to produce, in effect, an artificial recoil movement which willperform the necessary cocking action.

The invention comprises a cocking mechanism for a gun, incorporating ashaft rotatably mounted in the gun cradle or mounting and having, formedthereon, intersecting right and left-handed screw-threads; a retractormember mounted upon the shaft and provided with means for engaging andretracting the recoiling parts of the gun and with at least onethread-engaging member cooperating with the said screw-threads; andmeans for rotating the shaft whereby the retractor member, and

hence the recoiling parts of the gun, can be retracted, against springaction, by interaction between the thread-engaging member and one of thescrew-threads, to perform a desired cocking action whereafter furtherrotation of the shaft permits the return forward movement of therecoiling parts accompanied by interaction between the thread-engagingmember and the reverse screw-thread.

The spring action opposing the retraction will normally be suppliedmainly by a recoil return spring which may be assisted by varioussprings associated with the mechanisms to be cocked.

Various types of thread-engaging member may be employed, one examplebeing a pair of nuts mating respectively with the two screw-threads onthe shaft, with clutch means, reversible by contact with a bush at theend of its travel, for locking one or other of the nuts, according tothe direction of motion, against rotation relative to the retractormember. A preferred arrangement, however, comprises a half-nut rotatablymounted in a socket carried by the retractor member and having a threadportion for engaging the screwthreaded shaft, the axis of rotation ofthe half-nut being radial to that of the shaft. At the end of its travelin each direction, the half-nut is diverted from one screw-thread of theshaft to the other by engagement of its tread portion with a cam surfaceformed on the end face of a sleeve fixed to the shaft, which cam surfacecauses the half-nut to rotate in its socket. The term half-nut is usedherein to denote a member located alongside but not encircling the shaftand incorporating a thread engaging portion which co-operates with thescrew thread to produce relative longitudinal movement between thehalf-nut and the shaft.

The retraction and return movement may be accomplished by continuouslyrotating the shaft, manually or by other convenient means, throughoutthe cycle but it is preferred to allow the return movement to occurunder the action of the recoil return spring. With this arrangement itis desirable to use a slow pitch screw thread for retraction to providea mechanical advantage in favor of the operator or other rotating means,with a reverse thread of steep pitch to give a mechanical advantage infavor of the recoil return spring, an arrangement compatible with use ofthe half-nut type of thread-engaging member.

One form of the invention will now be described, by way of example only,with reference to the accompanying drawings, the single FIGURE of whichis a vertical section of part of the breech end of a weapon takenthrough the cocking mechanism.

A shaft 1 is rotatably mounted, parallel to the gun axis 2, in bearings3, 4 carried by the cradle 5 or a bracket attached thereto, one at eachend of the shaft 1, the bearings being retained and located by pins 3a,4a extending through the hearing but clear of the shaft. Formed on theshaft 1 are two intersecting screwthreads, one a right-handed thread 6of fairly slow pitch and the other a left-handed thread 7 ofsubstantially twice that pitch. Rearward of the shaft 1 is a handle 8,mounted on a short axle 9 aligned with the shaft 1 and rotatable in abush 10 carried by the rear wall 1 1 of the housing 5a which enclosesvarious mechanisms associated with the weapon. This wall is hinged 12 togive access to the interior of the housing and, to permit this, theforward end of the axle 9 has, formed thereon, a diametral key 13 whichengages a keyway 14 formed in a collar 15 fixed to the rear end of theshaft by a pin 16. Swinging the wall 11 outward to open the housing thusdisengages the axle 9 from the shaft 1 but re-engagement occurs when thehousing is closed again. The handle 8 incorporates a ratchet 17 whichpermits freewheeling of the axle 9, and hence the shaft 1, in aclockwise direction relative to the handle 8. Mounted on the shaft 1 andrestrained against rotation by engagement with a guideway 18 in thecradle, is a slide 19 which constitutes a retractor member and carries aforwardly extending hook member 20 for engaging a forward facing surfaceon the breech ring 21 of the gun 22 which can, thereby, be pulledrearwardly with the other recoiling parts of the gun 22. Formed on theslide 19 is a hollow, cylindrical boss 23 whose axis is radial to theshaft 1 and in which is mounted a cylindrical half-nut 24 whose innersurface is shaped to contact the outer surface of the screw-threads 6, 7on the shaft 1 and has, formed thereon, a raised thread portion 25 whichlocates in the groove of the shafts screw-thread. At each end of thescrew!-threaded part of the shaft 1 is a collar 26, 27, fixed to theshaft by a pin 26a, 27a, the end face of each collar adjacent thescrew-threads being shaped to provide a somewhat widened groove and toform a cam surface 28, 29 respectively, such that its engagement withthe thread portion 25 of the half-nut 24 will cause the half-nut to turnabout its axis whereby it is diverted from one screw-thread of the shaft1 to the other.

Starting from the rest position, clockwise rotation of the shaft 1, bymanual operation of the handle 8, will cause the half-nut 24 to travelrearward along the slow pitch, right-handed screw-thread 6 of the shaft,carrying the slide 19 and the recoiling parts of the gun rearwardagainst the action of the recoil return spring to perform the requiredcocking action. The arrangement of recoil return spring can take any oneof any one of many forms which are so well known in the art that thisitem is shown schematically only, at 30. When the half-nut 24 reachesthe rear end of the threaded portion of the shaft, its thread portion 25engages in cam surface 28 of the rear collar 26 causing the halfnut 24to rotate within the boss 23 so that the thread portion 25 is divertedinto the steeper pitch, lefthanded thread 7 of the shaft. Thereafter therecoiling pans run out forwardly under the action of the recoil returnspring while the shaft 1 free-wheels relative to the handle 8. Thisfree-wheel action allows a more rapid run-out than would be achieved bycontinued manual operation of the shaft. On arrival at the forward endof the shaft 1 the thread portion 25 of the halfnut" 24 is diverted intothe right-handed thread 6 again by engagement with the cam surface 29 onthe forward collar 27.

Variations in construction of the shaft, the retractor member and itsthread-engaging member within the scope of the invention will, ofcourse, readily occur to those skilled in the art. The details of themounting of the device, the rotating means and the means for engagingthe recoiling parts will be largely dictated by the design of the weaponto which the invention is applied.

1 claim:

1. In a gun incorporating recoiling parts carried in a mounting andwhich requires retraction of said recoiling parts relative to themounting to perform a desired cocking action and having spring meansresisting said retraction; a cocking mechanism comprising a shaftrotatably mounted in the gun mounting; intersecting right andleft-handed screw-threads formed upon said shaft, one of which threadsconstitutes a retracting thread and the other of which threadsconstitutes a reverse thread; a retractor member mounted upon saidshaft; means carried by said retractor member for engaging andretracting the recoiling parts of the gun; at least one thread'engagingmember carried by the retractor member and cooperating with thescrewthreads on the shaft; and means for rotating said shaft whereby theretractor member and, hence, the recoiling parts of the gun can beretracted against the action of said spring means, by interactionbetween the thread-engaging member and the retracting thread, to performa desired cocking action; means for diverting the thread engaging memberinto engagement with the reverse thread after retraction of therecoiling parts, whereafter further rotation of the shaft permits thereturn, forward movement of the recoiling parts accompanied byinteraction between the thread-engaging member and the reversescrew-thread; and means for returning the thread engaging member intoengagement with the retracting thread on completion of said forwardmovement.

2. A cocking mechanism as claimed in claim 1 wherein the thread-engagingmember comprises a half-nut rotatably mounted in a socket carried by theretractor member; and a thread-engaging portion carried by saidhalf-nut; the axis of rotation of the halfnut being radial to the shaftwhereby it can be rotated to align the thread-engaging portion witheither of the screw-threads on the shaft.

3. A cocking mechanism as claimed in claim 2 having a cam-surface ateach end of the screw-threaded portion of the shaft for engagement bythe thread-engaging ortion of the halfu at each end of its travel to iotate the half-nuti nits socket and divert its threadengaging portionfrom one screw-thread to the other.

4. A cocking mechanism as claimed in claim 1 wherein the reversescrew-thread is of steeper pitch than that engaged by thethread-engaging member during retraction of the recoiling parts.

5. A cocking mechanism as claimed in claim 1 wherein the recoiling partsare arranged to run-out under the influence of spring action and themechanism incorporates a ratchet device by which the means for rotatingthe shaft engages the shaft, whereby the shaft can rotate during run-outwithout further rotation of said means for rotating the shaft.

6. A cocking mechanism as claimed in claim 1 incorporating a half-nutrotatably mounted in a socket carried by the retractor member andconstituting the thread-engaging member; a thread engaging portionformed on said half-nut, the axis of rotation of the half-nut beingradial to the shaft whereby it can be rotated to align thethread-engaging portion with either of the screw-threads on the shaft; acam surface located at each end of the screw-threaded portion of theshaft and engageable by the thread-engaging portion of the half-nut torotate the half nut in its socket and divert it from one screw thread tothe other; and a ratchet device by which the means for rotating theshaft it connected to said shaft; the return forward movement of therecoiling parts being arranged to occur under the influence of springaction, the accompanying further rotation of the shaft occurring, byvirtue of the ratchet device, without further operation of the means forrotating said shaft; and the reverse screw-thread being of steeper pitchthan the screw-thread employed during retraction of the recoiling parts,whereby the mechanical advantage, during retraction of the recoilingparts, is in favor of the means for rotating the shaft and, during thereturn forward movement, is in favor of the spring action.

1. In a gun incorporating recoiling parts carried in a mounting andwhich requires retraction of said recoiling parts relative to themounting to perform a desired cocking action and having spring meansresisting said retraction; a cocking mechanism comprising a shaftrotatably mounted in the gun mounting; intersecting right andleft-handed screw-threads formed upon said shaft, one of which threadsconstitutes a retracting thread and the other of which threadsconstitutes a reverse thread; a retractor member mounted upon saidshaft; means carried by said retractor member for engaging andretracting the recoiling parts of the gun; at least one thread-engagingmember carried by the retractor member and cooperating with thescrew-threads on the shaft; and means for rotating said shaft wherebythe retractor member and, hence, the recoiling parts of the gun can beretracted against the action of said spring means, by interactionbetween the thread-engaging member and the retracting thread, to performa desired cocking action; means for diverting the thread engaging memberinto engagement with the reverse thread after retraction of therecoiling parts, whereafter further rotation of the shaft permits thereturn, forward movement of the recoiling parts accompanied byinteraction between the thread-engaging member and the reversescrew-thread; and means for returning the thread engaging member intoengagement with the retracting thread on completion of said forwardmovement.
 2. A cocking mechanism as claimed in claim 1 wherein thethread-engaging member comprises a ''''half-nut'''' rotatably mounted ina socket carried by the retractor member; and a thread-engaging portioncarried by said ''''half-nut''''; the axis of rotation of the half-nutbeing radial to the shaft whereby it can be rotated to align thethread-engaging portion with either of the screw-threads on the shaft.3. A cocking mechanism as claimed in claim 2 having a cam-surface ateach end of the screw-threaded portion of the shaft for engagement bythe thread-engaging portion of the ''''half-nut'''' at each end of itstravel to rotate the ''''half-nut'''' in its socket and divert itsthread-engaging portion from one screw-thread to the other.
 4. A cockingmechanism as claimed in claim 1 wherein the reverse screw-thread is ofsteeper pitch than that engaged by the thread-engaging member duringretraction of the recoiling parts.
 5. A cocking mechanism as claimed inclaim 1 wherein the recoiling parts are arranged to run-out under theinfluence of spring action and the mechanism incorporates a ratchetdevice by which the means for rotating the shaft engages the shaft,whereby the shaft can rotate during run-out without further rotation ofsaid means for rotating the shaft.
 6. A cocking mechanism as claimed inclaim 1 incorporating a ''''half-nut'''' rotatably mounted in a socketcarried by the retractor member and constituting the thread-engagingmember; a thread engaging portion formed on said ''''half-nut,'''' theaxis of rotation of the ''''half-nut'''' being radial to the shaftwhereby it can be rotated to align the thread-engaging portion witheither of the screw-threads on the shaft; a cam surface located at eachend of the screw-threaded portion of the shaft and engageable by thethread-engaging portion of the ''''half-nut'''' to rotate the half nutin its socket and divert it from one screw thread to the other; and aratchet device by which the means for rotating the shaft it connected tosaid shaft; the return forward movement of the recoiling parts beingarranged to occur under the influence of spring action, the accompanyingfurther rotation of the shaft occurring, by virtue of the ratchetdevice, without further operation of the means for rotating said shaft;and the reverse screw-thread being of steeper pitch than thescrew-thread employed during retraction of the recoiling parts, wherebythe mechanical advantage, during retraction of the recoiling parts, isin favor of the means for rotating the shaft and, during the returnforward movement, is in favor of the spring action.